CVE-2025-43554: Unchecked Bounds Write Vulnerability in Substance3D – Modeler

Overview

There is a recently disclosed vulnerability, identified as CVE-2025-43554, that affects Substance3D – Modeler versions 1.21.0 and earlier. The vulnerability is a serious concern as it allows an attacker to execute arbitrary code in the context of the current user, potentially compromising the system or leading to data leakage. It is critical to note that this vulnerability requires user interaction, as a victim needs to open a malicious file for the exploit to be successful. This blog post aims to provide an in-depth analysis of this vulnerability and provide necessary mitigation measures.

Vulnerability Summary

CVE ID: CVE-2025-43554
Severity: High – 7.8 (CVSS:3.x)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Substance3D – Modeler | 1.21.0 and earlier

How the Exploit Works

The CVE-2025-43554 vulnerability is a result of an out-of-bounds write condition within the Substance3D – Modeler software. When a user opens a specially crafted malicious file, the software fails to properly validate the size of user-supplied data before writing it to a fixed-length, stack-based buffer. This oversight leads to a buffer overflow, allowing an attacker to overwrite critical memory locations with their own arbitrary code.

Conceptual Example Code

Consider the following pseudocode which illustrates the basic premise of this exploit:

// Simulated function in Substance3D Modeler processing a user-crafted file
void process_file(char *filename){
char buffer[100];
FILE *file = fopen(filename, "r");
// buffer overflow occurs when the file contains more than 100 bytes
fread(buffer, 1, 500, file);
fclose(file);
// the overflowed buffer can alter program execution flow
}

In this scenario, the user-supplied data (the malicious file) is read into the buffer without checking its size, leading to a buffer overflow when the file contains more than 100 bytes. This overflow can be manipulated to alter the program execution flow, allowing an attacker to execute arbitrary code.

Mitigation Guidance

To mitigate this vulnerability, users are advised to apply the vendor’s patch as soon as it becomes available. Until the patch is released, use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary protection by detecting and blocking attempts to exploit this vulnerability. Further, users should avoid opening files from untrusted sources to minimize the risk of exposure.